Inmarsat response to the ACMA Discussion Paper:
Beyond 2020—A spectrum management strategy to address the growth in mobile broadband capacity
22 October 2015
General comments
Inmarsat thanks the ACMA for this discussion paper for and for the opportunity to comment.
Inmarsat provides mobile satellite services using our fleet of satellites which operate in L-band, C-band and Ka-band. We are currently building a new satellite that will operate in the 2 GHz MSS bands (1980-2010 MHz and 2170-2200 MHz) in Europe.
Many of the applications which drive the use of our satellite systems are driven by the growth in mobile broadband. The ever increasing demand for higher datarates is a challenge for satellite systems but is achieved, among other things, by the use of higher frequency bands and by adopting new spectrally efficient technologies. Satellite has a unique ability to provide communications to remote areas and is particularly important for provision of mobile broadband in areas not covered by terrestrial networks. Satellite systems will have a key role in providing mobile broadband throughout Australia.
Inmarsat concurs with the general thrust of the discussion paper that ensuring adequate spectrum for mobile broadband is an important consideration for regulators. However there is a grave danger of making bands available for mobile broadband which are not really needed for many years into the future, or are not needed at all. This is damaging to other services because the identification of new bands for mobile almost always means that incumbent services are displaced.
We courteously remind the ACMA of the need to maintain bands allocated to satellite services to support mobile broadband. This is particular relevant in the context of this Discussion Paper since some of the bands identified by the ACMA as possible future bands for mobile broadband are used by satellite networks, partly to support mobile broadband.Even a verypreliminary identification of some satellite bands for terrestrial mobile applications can instigate uncertainty for operators and customers, undermine the long term investments required by satellite operators and their customers, and thereby increasethe cost of satellite applications.
Furthermore, while some bands available for satellite applications have been proposed to be used by terrestrial mobile systems on a shared basis, the historical evidence suggests that sharing is not practicable. Almost all bands currently used for terrestrial mobile are used on an exclusive basis. We are quite sceptical about claims from the terrestrial mobile community that sharing is feasible with incumbent services. If a band really is used to a significant extent for mobile, then the incumbent service will most likely eventually be displaced from the band.
The need for additional bands for terrestrial mobile broadband in Australia
In Chapter 2 of the discussion paper: “Mobile broadband—Context”, the ACMA provides a thorough summary of the predictions for mobile broadband traffic growth and estimates of spectrum requirements for terrestrial mobile broadband. We note, as does the ACMA on page 16, that growth estimates by Cisco and Ericsson have been moderated in recent times, suggesting that the “hockey stick” projections of the past were overestimating traffic growth. We concur with the ACMA’s comment (page 17) that predictions even only 18 months ahead show a very large variance. It is clear that data traffic predictions more than a few years ahead are too unreliable to be of much use.
The ACMA also provides in Chapter 2 a summary of three studies which have estimated the spectrum requirements for mobile broadband. We agree with the reasons identified by the ACMA (page 17) that estimating spectrum requirements is very uncertain.
The ACMA mentions the use of Recommendation ITU-R M.1768-1, which was the methodology used to estimate global spectrum requirements for IMT. In 2006, that methodology was used to estimate spectrum requirements for mobile broadband in Report ITU-R M.2078. At that time, the estimated total requirements were 1300 MHz by 2015 and between 1280 and 1720 MHz by 2020. The methodology was used again in 2013 in Report ITU-R M.2290-0 (with different input assumptions), leading to an estimate of between 1340 and 1960 MHz by the year 2020.
As the ACMA rightly identifies, there has been analysis which raises serious doubts about the estimates contained in the ITU-R Reports. Regarding the results in Report ITU-R M.2078, it is now quite clear that the estimate of a requirement of 1300 MHz by 2015 was much too high. The bands currently identified for mobile broadband in Australia total 888 MHz in Regional areas (Table 1 on page 23), which is only 68% of the requirements suggested in Report ITU-R M.2078 for the current year. In Metropolitan and Remote areas of Australia, the available spectrum is lower still. This clearly demonstrates that the estimates in Report ITU-R M.2078 were much too high.
Regarding the more recent estimated requirements in Report ITU-R M.2290-0, as is indicated by the ACMA, there have been studies such as that by LS Telcom which have identified serious flaws in the input assumptions in those calculations, suggesting that those spectrum estimates for 2020 are significantly over estimated.
The ACMA also mentions the Real Wireless study performed for the UK regulator Ofcom. The ACMA should be aware that Inmarsat identified a significant error in that analysis. Traffic density figures that were initially given in petabytes per month per square kilometre should have been in terabytes per month per square kilometre, meaning that the traffic numbers used in the modelling were 1000 times higher than intended. Ofcom was informed of the error in the study, which is no longer being used as a reference by Ofcom.
Considering the very poor record of previous spectrum demand predictions, Inmarsat agrees with the ACMA’s conclusion (page 20) that forecasts for mobile growth and for mobile spectrum should not be relied upon for assessing terrestrial mobile spectrum requirements.
On page 27 the ACMA concludes: “Spectrum will continue to be a key enabler for many other, non-mobile broadband, services that provide economic and societal benefits to Australia. The associated requirement for spectrum to enable these services will continue but may vary over time.” Inmarsat highlights that with regard to our services (which include satellite mobile broadband), the requirement for spectrum will continue in the L-band MSS allocations, and in the C-band and Ka-band FSSallocations. There is also likely a need in the future for spectrum in the S-band MSS allocations. The services provided by Inmarsat in these bands are typically of high societal benefit (e.g. safety related communications for ships and aircraft, and provision of mobile broadband to remote areas with little terrestrial coverage). Furthermore, some Australian industries of high economic value (e.g. mining, oil exploration) are major users of Inmarsat services. It is important that the ACMA considers these and similar benefits provided by other satellite operators when considering making more bands available for terrestrial mobile.
The ACMA should also take into account that for many satellite applications, there are no practical alternative frequency bands. The bands available for satellite communication services are limited to those allocated to FSS, MSS or BSS in the Radio Regulations. In most cases, bands are allocated globally, meeting the needs of most satellite systems for global services. In the case of the L-band MSS frequency bands, there is no realistic alternative for many applications. The propagation characteristics at L-band are such that small terminals with omni-directional or low gain antennas operate but such terminals would not be feasible at higher frequency bands. Similarly, many C-band FSS applicationscannot be transitioned to other frequency bands due to the different technical and physical characteristics in Ku-band and Ka-band.Consequently, it is important that regulators make decisions which maintain the ability to operate satellite systems throughout the world. It is sometimes necessary for regulators to refrain from deploying terrestrial services in a particular band, even if that is considered to provide a higher value when viewed on a national basis.
On page 36, the ACMA concludes: “Increases in mobile broadband capacity will continue to be met through a combination of additional spectrum, improved technologies providing increased spectral efficiency, increased network infrastructure and new network topologies.” Inmarsat agrees that improved technologies and new topologies will increase mobile system capacity. It is apparent that there is a lot more that can be done to use the current bands more efficiently – for example increased deployment of LTE and its subsequent developments in place of the current 2G and 3G technology, and increasing the density of base stations. With this in mind, and with the uncertainty over the mobile traffic demands, it is not at all certain that additional spectrum will be required for terrestrial mobile. Despite this uncertainty, which the ACMA acknowledges, the ACMA has identified 12 different bands at different stages of analysis that might be made available for mobile broadband(Table 3 on page 49).
On page 46, the ACMA seeks comments on the factors to be taken into account when assessing the highest value use of a band. As already mentioned above, Inmarsat’s satellite services provide high value societal benefits, for example: safety related communications for ships and aircraft; emergency communications; mobile broadband in areas beyond terrestrial network coverage. These benefits are difficult to quantify in financial terms, but are important nonetheless and should be taken into account in the decision making.
There have been studies conducted recently by Plum and Frontier Economics, claiming that high benefits arise from the refarming of C-band spectrum from satellite use to terrestrial use. The ACMA should be aware of a study by economic consultants VVA[1] for ESOA and the GVFwhich have identified significant shortcomings in those studies[2].
Proposed work program
The ACMA asks for comments on the proposed work program.
On page 50, the ACMA identifies several bands in the category of “Stage 1: Initial investigation”. This includes the band 1427-1518 MHz, which is adjacent to the MSS downlink band, 1518-1559 MHz[3]. Inmarsat is concerned about potential interference from IMT systems to MSS systems. Studies have taken place in the run up to WRC-15 which are summarised in the ITU-R CPM Report[4] (see section 1/1.1/4.1.2.9). Also, some studies have been undertaken in CEPT project team ECC PT1. While the studies are not yet complete, it is clear that some technical restrictions would be needed on IMT to ensure compatibility with the MSS. The technical restrictions would most likely consist of a guard-band between IMT and MSS and an out-of-band emission mask. The ACMA has identified that the impact on aeronautical telemetry services and fixed services will need to be considered. The potential impact on the MSS should also be considered.
The ACMA also identifies the bands 1980–2010 MHz and 2170–2200 MHz (2 GHz MSS bands) as being in “stage 1”. As we commented in our response to the ACMA’s consultation on the “Communication with a Space Object Class Licence” in June 2015, Inmarsat believes that these bands should be retained as MSS bands.
The bands 1980–2110 MHz and 2170–2200 MHz are allocated to the MSS internationally and are used or planned to be used by MSS systems in many countries. Inmarsat is one of two MSS operators selected to provide MSS services in Europe. The Inmarsat 2 GHz MSS satellite (“Europasat”) is currently under construction, planned for launch in 2016. This system is aimed primarily at provision of services to airlines, including in-cabin WiFi for airline passengers.
The Europasat satellite will not provide coverage of Australia but as aeronautical services are global by nature, the spectrum should remain available for future growth of the service. This system and developments by other MSS operators for systems in these bands are illustrative of the exciting new MSS systems that are in the process of being deployed. Services similar to those provided by Europasat or other MSS services can be expected to be deployed in Australia as part of an international footprint in the future.
The ACMA has opened these bands for interim use for Television Outside Broadcast (TVOB) while the band is not used by the MSS in Australia. Inmarsat is content with that approach, particularly insofar that this allows the 2 GHz MSS bands to be used for the period during which there are no MSS systems providing service in Australia. However these bands should remain available for the MSS in the longer term.
If these bands were to be made available for terrestrial mobile systems, there would be potential for interference to MSS satellites from terrestrial mobile operations in the band 1980-2010 MHz. ITU-R working parties 4C and 5D have instigated sharing studies on compatibility between IMT and MSS and while the studies are not complete, the preliminary results show the possibility for harmful interference. If terrestrial mobile systems were to be deployed in Australia in this band, harmful interference could occur to the Inmarsat Europasat satellite and therefore the ACMA should not proceed with any plans for terrestrial mobile in these bands.
The ACMA also identifies the band 3575–3700 MHz as being at “stage 1”. Inmarsat wishes to remind the ACMA that part of this band is used to receive satellite downlink signals at our gateway earth station in Perth, and will continue to be used for the foreseeable future. Any use of this band by terrestrial mobile systems would need to protect this earth station and others operating in this band in Australia. Given the very large separation distances that would be required for IMT systems to avoid causing interference to FSS earth stations, and the poor coverage possible by mobile systems in this relatively high frequency band, Inmarsat does not believe that this is an attractive band for mobile systems.
Concluding comments
Inmarsat again thanks the ACMA for the opportunity to comment on this discussion paper. In summary, we are concerned by several of the frequency bands that the ACMA identifies as possible terrestrial mobile bands in the future, specifically the bands 1427-1518 MHz, 1980–2010 MHz, 2170–2200 MHz and 3575–3700 MHz. We therefore request that the ACMA carefully considers the impact on our services and those of other satellite operators before proceeding further with any of these bands.
Inmarsat is content for this contribution to be published on the ACMA website.
For further information, please contact Mr Paul Deedman, Manager, Spectrum Regulation at .
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[2]Summary available at
[3] Only the band 1525-1559 MHz is currently available in Australia
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